Early Initiation of Natural Convection in an Open Porous Layer Due to the Presence of Solid Conductive Inclusions

Abstract

The effects of solid conductive blocks on the initiation of convection in a porous medium are reported in this paper. A two-dimensional convective code was used to determine the temperature field, the structure of the motion, and the global heat transfer through a composite medium consisting of permeable and impermeable areas. Influence of the size of impermeable regions on convection as well as the effect of the distance between these solid blocks was studied in terms of Nusselt number and maximum of the stream function. The predicted heat transfer in this type of composite medium, obtained with the code, was compared with experimental results where the porous medium is a low-density insulating material in which some wood joists are included. This configuration corresponds to the layer of insulation on the floor of a residential attic.